Although athletes have said EPO is in widespread use, few have tested positive. Most of the athletes who have been linked to doping in recent years have been caught not through drug testing, but rather through criminal investigations. In the August 2006 issue of the journal Blood, the American lab accredited to conduct EPO testing reported only 9 positive tests out of 2,600 urine samples.

The new study may help explain why: the test simply failed.

The study, to be published Thursday in the online edition of the Journal of Applied Physiology, was conducted last summer and fall by a renowned lab in Denmark, the Copenhagen Muscle Research Center. The investigators gave eight young men EPO and collected urine samples on multiple occasions before, during and after the men were doping. The men’s urine samples were then sent to two labs accredited by the World Anti-Doping Agency, and EPO tests were requested.

The first lab found some samples positive and a few others suspicious. (A suspicious result does not bring sanctions for doping.) The lab also declared a sample positive, although the man had stopped taking the drug and it should have been gone from his urine. His previous urine sample, obtained when he was taking EPO, was negative in this lab’s test.

The second lab did not deem any urine sample positive for EPO and found only a few to be suspicious. The two labs did not agree on which samples were suspicious.

… [Investigators] realized they had an opportunity to investigate the validity of the EPO test. So, without telling the anti-doping labs what they were doing, the investigators sent the men’s urine samples for EPO testing.

One of the two labs, which the researchers refer to as Lab B in their paper, never declared a sample positive, even when the men were taking high doses of EPO every other day. Lab A was inconsistent. It found EPO during the high dose phase. But in the maintenance phase, it found EPO in only 6 of the 16 samples.

Great news, eh?

Not like “I never tested positive” meant a whole lot before, but with this news, anyone who claims not to have doped and “never testing positive” can have the “yeah, but the tests detect it every time” argument thrown back at them …

And clean athletes will never be able to prove that they haven’t doped … all winning riders are going to fall under suspicion.